The act of loading a horse for ground transport, is an experience that most horses endure at least once during their lifetime. Horses that are reluctant or refuse to load create problems for both owners and veterinarians.
Horses are naturally neophobic or afraid of new things and since the average horse trailer has a dark interior, poor or insecure footing and an unstable ramp system, many horses can become paralysed with fear.
Horses acquire trailering problems primarily through improper training or bad experiences. To some extent genetics will interact with learning and some horses are more reactive or more predisposed to potential problems because of bad experiences or poor training, when other horses may never develop a problem dispite improper training.
The experience that a horse has accumulated through past trailering can have a profound impact on how it will perform in the future. When an owner attempts to urge a horse onto a trailer through hitting or any other form of rough handling, the horse will begin to associate the pain or rough treatment with loading. Thoughtless driving (swerving around a car at high speeds or turning at sharp angles) can either slam the horse against the trailer wall or pull on its lead shank which will reinforce the horse's fear of trailers. The expression of this fear can include rearing, kicking and/or backing up when approaching or entering a trailer.
Teaching a horse to move in response to a touch on the body is the easiest method to train a horse to load. The handler should hold the horse with a halter and lead rope (preferably a person who has not loaded the horse before). A good non-threatening stimulus like a lunge whip with a cloth tied to the end will encourage a horse to move in a particular direction. The proper technique is to urge the horse to approach the trailer without allowing it to enter. After a few successful trails the horse's hindquarters should be tapped to encourage entry. If on the first attempt only partial entry is achieved, usually a few additional trails will result in loading. The handler should then repeat the procedure until the horse can be loaded without resistance.
The best method to desensitize and counter-condition a horse in a non-immediate situation is to reward the horse for loading itself. This method may take days, weeks or months to complete, although it is by far the most successful. On average, a month of training prior to the trip should be sufficient.
The trailer should be placed in a corral and secured to prevent tipping while the daily ration for the horse is placed in the bottom of the trailer ramp. With each successive day the food should be placed a little farther up the ramp so that eventually the horse must enter in order to feed. After desensitization is complete and the horse has loaded successfully, the handler should continue to place the food in the trailer until he/she is confident the problem has been eliminated. However, even on completion of this training program some horses may be reluctant to the trailer in a strange place. This problem can be eliminated if the handler is willing to implement the above procedure at different locations. The horse will then be able to trailer regardless of the surroundings. A more drastic method to encourage loading is to make the trailer the only means of escape from an unfamiliar place.
A rear-facing trailer may solve trailering problems for horses that refuse to enter conventional trailers. The handler can convert the trailer's ramp into a platform and the horse can be backed in. This method eliminates the fearful connection to conventional trailers where the head of the horse is always first.
If the problem is acute and the horse needs to be quickly loaded there are several methods available that do not elicit pain. One is simple pushing. Typically, long butt ropes are tied on each side of the trailer to apply pressure to the back legs of a horse encouraging it to enter. If the horse becomes entangled, the handler can easily drop the ropes. In cases where only mild reluctance to enter the trailer is shown, two people can simply join hands behind the horse and use their arms to apply pressure to its rump.
Horses are herd animals, (and as such will naturally want to follow another horse). Placing a calm horse in the trailer prior to loading, increases the chance of a quiet load. This, method is generally effective only on a quiet animal. The herd mentality can also be used to ease loading of foals by placing their dam in the trailer before loading.
Remembering that the basis of some trailering problems is too lengthy a first trailer experience, the first few trips should only be .5 to 1 mile ending with a grazing session. A handler can then habituate their horse to the sensation of a moving vehicle while rested.
In extreme cases sedatives such as xylazine are used. Their effectiveness can be increased if administered to an animal before it has become excited or frightened. Desensitization, through repeatedly sedating an animal and loading it, several times a day for one week has met with some success. However, most horses will not remember what they learned in the drugged state; a principle called state independent learning. A gradual increase in dose over several sessions can eliminate this problem. Despite their effectiveness, sedative use can be detrimental to horses in that they can impair a horse's ability to perform, result in elimination from competitions where drug testing occurs and cause loss of equilibrium. This can then increase fear and anxiety of trailering which compounds the trailering problem.
Crowell-Davis, S.; Preventing Trailering Problems: Part I. Equine Practice. 1986.8:10, p31-32, 36.
Crowell-Davis, S.; Preventing Trailering Problems: Part II. Equine Practice. 1987.9:1, p31-32.
Evans, J., Borton A., Hintz H., Leck, L.V.; The Horse 2nd ed. 1990. Wh.H. Freeman and Co.: New York.
Houpt, K. Domestic Animal Behavior. 2nd ed. 1991, Iowa State University Press: Ames, Iowa.